07-25-2007 10:07 AM - edited 03-03-2019 06:01 PM
Hello all,
I have recently connected my site to a remote office using a 9.744 Mbps point-to-point serial circuit over Satellite. I am seeing very strange errors on the interfaces and would appreciate assistance. Please reference the attached network diagram with the follow-up post containing the "show interfaces" below. The connection from my building to the satellite teleport is over ATM. I am seeing "output drops" on both sides of ATM circuit. The ATM circuit is one 9.744 Mbps PVC. I am also seeing errors on both HSSI interfaces. The HSSI circuit is timed off the satellite modem that is connected to the HSSI interface of Router B. I noticed by doing a show controllers that the receicved timing on the HSSI interface moves from 9743538 to 9745120 approximtely once every 30 seconds. However, I can not directly correlate the timing drift to the interface errors.
Thank you for your help.
07-25-2007 10:08 AM
Router A ATM Interface (ATM 2/0):
RouterA#sh int atm 2/0
ATM2/0 is up, line protocol is up
Hardware is RS8234 ATM DS3
Description: ATM Trunk
MTU 4470 bytes, sub MTU 4470, BW 45000 Kbit, DLY 190 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ATM, loopback not set
Encapsulation(s): AAL5
1023 maximum active VCs, 2 current VCCs
VC Auto Creation Disabled.
VC idle disconnect time: 300 seconds
Last input 00:00:01, output 00:00:00, output hang never
Last clearing of "show interface" counters 5w0d
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 8901043
Queueing strategy: Per VC Queueing
30 second input rate 131000 bits/sec, 14 packets/sec
30 second output rate 47000 bits/sec, 14 packets/sec
121292189 packets input, 741762298 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 5 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
112122802 packets output, 3956918578 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
Router B ATM Interface (atm 4/0):
RouterB#sh int atm 4/0
ATM4/0 is up, line protocol is up
Hardware is RS8234 ATM DS3
Description: ATM
MTU 4470 bytes, sub MTU 4470, BW 9744 Kbit, DLY 190 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ATM, loopback not set
Encapsulation(s): AAL5
1023 maximum active VCs, 1 current VCCs
VC Auto Creation Disabled.
VC idle disconnect time: 300 seconds
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 1d22h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 194973
Queueing strategy: Per VC Queueing
30 second input rate 43000 bits/sec, 8 packets/sec
30 second output rate 8000 bits/sec, 7 packets/sec
13834546 packets input, 3469090240 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
15460961 packets output, 123454412 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
07-25-2007 10:08 AM
Router B HSSI interface (hssi 3/0):
RouterB#sh int hssi 3/0
Hssi3/0 is up, line protocol is up
Hardware is M1T-HSSI-B
Description: SATCOM LINK
Internet address is 10.1.2.5/30
MTU 4470 bytes, BW 9744 Kbit, DLY 200 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open
Open: IPCP, crc 16, loopback not set
Keepalive set (10 sec)
Restart-Delay is 0 secs
Last input 00:00:03, output 00:00:00, output hang never
Last clearing of "show interface" counters 02:52:13
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
30 second input rate 6000 bits/sec, 6 packets/sec
30 second output rate 0 bits/sec, 0 packets/sec
128737 packets input, 17418447 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 parity
584 input errors, 574 CRC, 0 frame, 5 overrun, 0 ignored, 5 abort
138174 packets output, 87933979 bytes, 0 underruns
0 output errors, 0 applique, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions LC=down CA=up TM=down LB=down TA=up LA=down
HSSI DTE, received clockrate 9745120
HSSI DTE, received clockrate 9743538
Router C HSSI Interface (hssi 1/0):
RouterC#sh int hssi 1/0
Hssi1/0 is up, line protocol is up
Hardware is M1T-HSSI-B
Description: SATCOM LINK
Internet address is 10.1.2.6/30
MTU 4470 bytes, BW 9744 Kbit, DLY 200 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open
Open: IPCP, crc 16, loopback not set
Keepalive set (10 sec)
Restart-Delay is 0 secs
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 2d02h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 9917
Queueing strategy: fifo
Output queue: 0/40 (size/max)
30 second input rate 24000 bits/sec, 8 packets/sec
30 second output rate 7000 bits/sec, 8 packets/sec
15556907 packets input, 1154275136 bytes, 0 no buffer
Received 0 broadcasts, 202 runts, 0 giants, 0 throttles
0 parity
4858695 input errors, 2514675 CRC, 0 frame, 1380169 overrun, 0 ignored, 963851 abort
18890347 packets output, 1964671150 bytes, 2316 underruns
07-25-2007 11:14 AM
Hi,
only router C has a severely errored interface, can you have the satellite modem checked for correct SNR as likely the problem lies in there.
As you see on router B the HSSI clock can fluctuate a little without causing any problem.
07-25-2007 01:17 PM
Thank you very much for the reply. We're currently looking into replacing the SAT modem connected to router C. The circuit had been running pretty well for about 4 weeks until we begun seeing errors this past week. What concerns me are the output packet drops on the ATM interface. I have noticed the clock fluctuating on the HSSI interface from 9743538 to 9745528, while the ATM is a constant 9744000. Do you think that the mismatch of speeds could be causing this? If not, do you have any ideas on how I could troubleshoot?
07-25-2007 05:32 PM
Hi, if had worked 4 fine weeks it's just a matter of checking something on the dish and related equipment and fix it. For example a faulty lnb can bring SNR low enough for the error correction on the sat link not suffice anymore.
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